Ink fountain roller device for a printing press

ABSTRACT

A fountain roller device for a printing press has a fountain roller with an axially elongate preferably spiral shaped groove in its peripheral wall and an ink knife coacting with the peripheral wall of the fountain roller to control the thickness of the ink layer on the same by the width of the gap between the knife and the roller. Fibers and paper particles as may be contained in the ink will accumulate in this groove and are removed therefrom as the roller rotates, assisted if desired by the sweeping action of a roller with an elastically soft surface intermittently engaging the fountain roller thereby obtaining a continuous self-cleaning of the gap.

[ Sept. 12, 1972 [54] INK FOUNTATN ROLLER DEVICE FOR A PRINTING PRESS [72] Inventor: Karl-HeinzKrochert,Offenbach am Main, Germany [73] Assignee: Roland Offsetmaschinenfabrik Faber & Schleicher AG, Offenbach am Main, Germany [22] Filed: April 9, 1970 [21] -Appl.No.: 26,945

[30] Foreign Application Priority Data April 15, 1969 Germany ..P l9 18 987.8

[52] US. Cl ..101/350, 101/363 [51] Int. Cl. ..B41f 31/06, B4lf 31/14 [58] Field of Search ..101/350, 351, 363, 364, 365,

Roberts et al. ..101/148 2,578,921 12/1951 Cramer 101/350 2,530,282 11/1950 Brodie et al. 101/350 2,240,762 5/1941 Dietrich l0l/350 2,887,044 5/1959 Smejda ..l0l/365 X FOREIGN PATENTS OR APPLICATIONS 626,200. 7/1949 Great Britain ..101/350 Primary Examiner-4. Reed Fisher Attorney-Bane, Baxley & Spiecens [57 ABSTRACT A fountain roller device for a printing press has a fountain roller with an axially elongate preferably spiral shaped groove in its peripheral wall and an ink knife coacting with the peripheral wall of the fountain roller to control the thickness of the ink layer on the same by the width of the gap between the knife and the roller. Fibers and paper particles as may be contained in the ink will accumulate in this groove and are removed therefrom as the roller rotates, assisted if desired .by the sweeping action of a roller with an elastically soft surface intermittently engaging the fountain roller thereby obtaining a continuous selfcleaning of the gap.

roller device in which the fountain roller of the device coacts with the ink knife to control the thickness of the ink layer and in which the ink is conveyed by engagement of the fountain roller with a pick-up ductor roller via ink roller to a printing plate.

BACKGROUND venieritly varied in the direction of the axis of the foun tain roller. Such differ'entialsetting of the ink layer per: mitsqadapta'tion of the ink requirement to the specific requirements of the material to be printed upon. It is also possible to stop the inkingof selected areas-of the ductor completely, for instance when the printer wants toch'ange from large sheet-material to smaller sized material. I

It is a general experience in the printing industry that the comparatively narrow gap between the ink knife and the peripheral wall of the fountain roller tends to become clogged by accumulations of dirt or paper particles and other impurities, thereby causing an interruption of theinklayer. i

One of the remedies frequently used by printers is to enlarge the gap either along its entire length or partly until the accumulations are flushed out, whereupon the knife is reset as required. Another remedy is to clean the entire ink knife.

Either remedy entailsloss of time andthe quality of the obtained prints suffers due to the changes in the thickness of the ink layer when and while the gap is widened. v

Modem high speed printing presses cause increased pulls and strains on the sheet material to be printed. Accordingly, there is an increased likelihood that small pieces of sheet material and of fibers are torn out and find their wayinto the ink. It has been found that with high speed printing presses clogging of the gap between the knife and the fountain roller is a rather frequent occurrence.

' Swiss Pat. No. 408,969 discloses a method in which the ink supply is maintained comparatively free of impurities by continuously agitating or turning over the ink. This method may reduce the frequency of clogging of the gap, but it is economically not practical and also cannot be used with all types of inks.

US. Pat. No. 3,037,451 shows an arrangement in which'the gap between the ink knife and the fountain roller or ink supply roll is periodically enlarged. Such periodic enlargement of the gap may reduce the danger of clogging of the gap due to small pieces of paper, and other foreign particles contained in the ink supply, but it has the disadvantage that the quantity of ink passing through the gap and hence the thickness of the ink layer on the fountain roller are periodically changed. As pointed out before, it is highly desirable to maintain the flow of ink to the sheet material to be printed upon as constant as possible to avoid inferior printing results.

THE INVENTION lt is an object of the invention to provide a novel and improved fountain roller device in which clogging of the gap between the fountain roller and the ink knife is effectively avoided without entailing the disadvantages of the devices as heretofore known for the purpose. Another important object of the invention is to provide a novel and improved fountain roller device of the general kind above referredto inwhich the gap is continuously self-cleaning. I

Still another important object of the invention is to provide a novel and improved fountain roller device of the general kind above referred to in which the shape of the fountain roller is such that the thickness of the ink layer on the fountain roller can'be accurately controlled and be set for very narrow dimensions. A fountain roller with a substantially circular cross-section has been found to be particularly advantageous.

' vantages, an other objects, featuresand advantages which will be pointed out hereinafter are obtained by providing in the peripheral wall of the fountain roller at least one axially elongate groove.

Tests have shown that fibers, small pieces of sheet material and other impurities which may be present the ink will automatically accumulate in this groove and are also pressed into the groove by the action of the ink knife. As a result, the gap itself will always remain clean and accumulations in the groove will automatically leave the same as the fountain roller rotates. Cleaning of the groove can be assisted by engagement of the fountain roller with a further roller which preferably has an elastically softsurface. This further roller will sweep out all accumulations in the groove. Accordingly, the fountain roller is continuously and automatically cleaned. It has been found that the desired cleaning action is obtained even if the depth of the groove is as low as 0.2 mm.

According to one preferred aspect of the invention, the groove in the fountain roller wall is spirally shaped. The use of such spiral groove has the advantage that the ink knife cannot cover the entire length of the groove in any position thereof. A further advantage of a spiral groove is that the ink knife cannot follow the outline of the groove as it may tend to do if the force pressing the knife toward the fountain roller is high, or the knife has a shape causing it to follow the outline of the groove. As is evident, while the knife either overlies the entire groove or follows the contour of the groove there will be no accumulations of impurities in the groove. Moreover, the spiral shape of the groove has the advantage that accumulations therein distribute themselves substantially uniformly in the direction of the fountain roller axis and also in circumferential direction.

According to a further aspect of the invention, the rear wall of the groove as seen in the rotational direction of the fountain roller is substantially radially disposed with reference to the axis of the fountain roller. The rear wall of the groove when thus oriented,

constitutes in effect a milling or cutting tooth which continuously strips off any impurities which may adhere to the ink knife.

According to another advantageous arrangement, the grove has a substantially triangular cross-section. The rear side of the triangle as seen in the rotational direction of the fountain roller is preferably radially disposed and shorter than the other sides of the triangle. It has been found that a groove thus shaped has a particularly effective cleaning action. Tests have shown that a triangular groove as just defined has the aforedescribed milling capability and is also sufficiently open to permit complete removal of any accumulations therein by engagement with an intermediate roller with a preferably elastically soft surface. Such intermediate roller will sweep the groove clean and carry away accumulations removed from the groove.

The intermediate roller may be ductor roller which is intermittently moved into and out of engagement with the fountain roller. A particularly effective cleaning action is obtained when the rotational speeds of the foun-' tain roller and the intermediate roller are different from each other at the time of engagement. Such engagement at differential speeds can be readily obtained by control means suitable for the purpose and well known in the art.

DETAILED DESCRIPTION OF THE INVENTION In the accompanying drawing, several preferred embodiments of the invention are shown by way of illustration and not by way of limitation.

In the drawing:

FIG. 1. is an elevational, partly sectional diagrammatic view of a fountain roller device according to the invention;

FIG. 2 is a fragmentary view of a modification of the fountain roller of FIG. 1 on an enlarged scale;

' FIG. 3 is an end view of FIG. 2; and

FIG. 4 is a diagrammatic perspective view of the fountain roller according to FIG. 1 on an enlarged scale.

Referring now to the figures more in detail, the fountain roller device exemplified in FIG. 1 comprises a rotatable fountain roller 1 which coacts with the end 5 of a ink knife 2. The knife is secured by screws 3 or other suitable fastening means to a holder 4. Lengthwise spaced set screws 6 (only one screw is visible) serve to adjust the position of the knife, and more specifically, of the portion 5 thereof with reference to the peripheral wall of fountain roller 1. As is evident, the setting of screws 6 controls the width of the gap between the knife and the peripheral wall of the fountain roller and this width, in turn, controls the thickness of the ink layer on the fountain roller.

A supply of ink 7 is kept in a pocket defined by fountain roller 1 and knife 2 as it is clearly shown in FIG. 1.

The fountain roller device further comprises a roller 8 such as a ductor roller and a roller 10 such as an ink roller. Roller Sis mounted on an arm 9 which is pivotal about a pivot and alternately and intermittently pivoted into engagement with fountain roller 1 and ink roller 10. Drive means for effecting such reciprocating movements of roller 8 are well known in the art; they do not constitute part of the invention and are hence not described in detail. As is apparent, roller 8 when in engagement with fountain roller 1 will pick up ink thereon and transfer it to ink roller 10 for conveyance to a printing plate (not shown).

As shown in FIG. 1 and more clearly in FIG. 4, the peripheral wall of the fountain roller includes a groove 11 which extends along the length of the fountain roller preferably at a spiral slant with the rotational axis thereof. As previously explained, such slant has the advantage that the knife 2 cannot engage the entire length of the groove in any angular position of the fountain roller. The groove has an approximately triangular out-. line as seen in the cross-section at a right angle to the axis of the roller. The sides of the triangle are formed by groove walls 13 and 15 and the base by an imaginary continuation of the peripheral wall of the roller. The rear side 13 of the groove, that is, the trailing side of the groove as seen in the rotational direction of the fountain roller, is substantially radially disposed with reference to the axis of the .fountain roller. The triangle side 15 adjacent to side 13 is preferably longer than this side and intersects'the peripheral wall of the fountain roller, as clearly shown in FIG. 4. Sides 13 and 15 are advantageously joined by a curved wall portion 14 which may have a circular curvature. Due to the described configuration of the groove, the rear edge thereof acts as a milling or cutting tooth to scrape off impurities as may adhere to the knife.

FIGS. 2 and 3 show a fountain roller 16 with a spiral shaped groove 17 in its peripheral wall; more specifically, a groove which forms several turns within the length of the fountain roller. In other words, the pitch of the groove 17 of FIG. 2 is shallower than the pitch of groove 11 of FIG. 4.

Groove 17 may have a substantially triangular crosssection as described in connection with FIG. 4, or as shown it may have a rectangular cross-section. Rear wall 13' of the groove is again radially oriented with respect to the axis of the fountain roller to obtain the aforedescribed desirable milling action.

The groove is substantially self-cleaning but cleaning of the groove may be assisted either by the sweeping action of roller 8 or a special cleaning tool shaped in accordance with the cross-section of the groove.

Of course, the rectangular cross-section of FIG. 2 may be used for fountain roller of FIG. 4 also.

While the invention has been described in detail with respectto certain now preferred examples and embodiments of the invention, it will be understood by those skilled in the art, after understanding the invention, that various changes and modifications may be made without departing from the spirit and scope of the invention, and it is intended, therefore, to cover all such changes and moficiations in the appended claims.

What is claimed is:

1. An ink fountain roller device for the inking device of a printing press, said device comprising in combination:

a fountain roller for taking up ink from a supply of ink having a continuously cylindrical wall surface, said wall surface including a groove spirally extending in the direction of the roller axis, said groove having an outline in a cross-section at a right angle to the roller axis such that the rear wall of the groove as seen in the rotational direction of the fountain roller is disposed in a generally radial direction with reference to the fountain roller axis, constituting a trap for trapping therein solid particles contained in an ink layer on the fountain roller; 1 a receptacle for a supply of ink, said fountain roller being mounted to dip into said receptacle to take up ink from the ink supply therein; and an ink knife extending parallel to the axis of said roller, said knife coacting with the cylindrical wall surface of said fountain roller and being set to define a gap between the knife edge and the roller wall surface for controlling the thickness of an ink layer thereon by the width of the gap. between the knife edge and the cylindrical wall surface of the v roller and for sweeping particles into said groove. 2. The device according to claim 1 and comprising a ductor roller rotatable about an axis parallel to that of the fountain roller and having a cylindrical resilient wall surface andpivot means supporting said ductor roller for pivoting said roller intermittently into and out of engagement with the cylindrical wall surface of the fountain roller thereby sweeping accumulations of particles out of said groove thereby removing the same from the roller.

3. The device according to claim 1 wherein said groove has a triangular outline in a cross-section at. a right angle to the roller axis, the trailing side of the triangle as seen in the rotational direction of the fountain roller being disposed in generally radial direction with reference to the fountain roller axis, and the side of the triangle adjacent to said rear side intersecting the cylindrical wall surface of the fountain roller.

4. The device according to claim 3 wherein said sides of the triangular groove are joined by a curved side wall portion.

5. The device according to claim 3 wherein said generally radially disposed side is shorter that the adjacent side. 

1. An ink fountain roller device for the inking device of a printing press, said device comprising in combination: a fountain roller for taking up ink from a supply of ink having a continuously cylindrical wall surface, said wall surface including a groove spirally extending in the direction of the roller axis, said groove having an outline in a cross-section at a right angle to the roller axis such that the rear wall of the groove as seen in the rotational direction of the fountain roller is disposed in a generally radial direction with reference to the fountain roller axis, constituting a trap for trapping therein solid particles contained in an ink layer on the fountain roller; a receptacle for a supply of ink, said fountain roller being mounted to dip into said receptacle to take up ink from the ink supply therein; and an ink knife extending parallel to the axis of said roller, said knife coacting with the cylindrical wall surface of said fountain roller and being set to define a gap between the knife edge and the roller wall surface for controlling the thickness of an ink layer thereon by the width of the gap between the knife edge and the cylindrical wall surface of the roller and for sweeping particles into said groove.
 2. The device according to claim 1 and comprising a ductor roller rotatable about an axis parallel to that of the fountain roller and having a cylindrical resilient wall surface and pivot means supporting said ductor roller for pivoting said roller intermittently into and out of engagement with the cylindrical wall surface of the fountain roller thereby sweeping accumulations of particles out of said groove thereby removing the same from the roller.
 3. The device according to claim 1 wherein said groove has a triangular outline in a cross-section at a right angle to the roller axis, the trailing side of the triangle as seen in the rotational direction of the fountain roller bEing disposed in generally radial direction with reference to the fountain roller axis, and the side of the triangle adjacent to said rear side intersecting the cylindrical wall surface of the fountain roller.
 4. The device according to claim 3 wherein said sides of the triangular groove are joined by a curved side wall portion.
 5. The device according to claim 3 wherein said generally radially disposed side is shorter that the adjacent side. 